Regulating device



Dec. 20, 1960 F. c. REGGIO 2,965,179

REGULATING DEVICE Original Filed Nov. 18, 1942 4 Sheets-Sheet 1 TOREDUCE SPEED INVENTOR F. C. REGGIO REGULAIING DEVICE Dec. 20, 1960 4Sheets-Sheet 2 Original Filed Nov. 18, 1942 IN VENTOR Dec. 20, 1960 F.c. REG GlO REGULATING DEVICE 4 Sheets-Sheet 3 Original Filed NOV. 18,1942 INVENTOR.

I55 I54 I56 /55 Dec. 20, 1960 F. C. REGGIO REGULATING DEVICE OriginalFiled Nov. 18, 1942 4 Sheets-Sheet 4 INVENTOR United States PatentREGULATING DEVICE Ferdinando Carlo Reggio, Tampa, Fla. (R0. Box 692,Norwalk, Conn.)

Division of application Ser. No. 694,824, Nov. 6, 1957, now Patent No.2,910,969, dated Nov. 3, 1959, and application Ser. No. 402,452, Jan. 6,1954, now Patent No. 2,812,746, dated Nov. 12, 1957, which is acontinuation of abandoned application Ser. No. 466,041, Nov. 18, 1942.This application Mar. 30, 1959, Ser. No. 803,055

15 Claims. (Cl. 170135.72)

This invention relates to regulating systems such as speed governors orsimilar control apparatus provided with stabilizing or anticipatorymeans to prevent hunting, secure automatic compensation for certainvariables or regulate the rate of response of the system to changes inthe controlling operating conditions. The instant application is adivision of my application Serial No. 694,824 filed November 6, 1957,now US. Patent No. 2,910,969 and application Serial No. 402,452 filedJanuary 6, 1954, now Patent No. 2,812,746 dated November 12, 1957, whichis a continuation of my application Serial No. 466,041 filed November18, 1942, now abandoned.

One of the objects is to provide a speed regulating system which iscomparatively simple and compact, requires a small number of movingparts and is relatively inexpensive to manufacture.

Another object is to provide a speed regulating system including a servomotor, a pilot valve therefor actuated in response to speed variations,and means for applying to the pilot valve a compensating, anticipatoryor restraining fiuid pressure load which varies with changes inpreselected operating conditions. i

A further object is to provide a simple and accurate speed regulatingsystem including a speed governor and one or more devices operativelyconnected with the governor for biasing the same in response to changesin one or more operative conditions affecting the speed to be regulated.

Still another object resides in the provision of anticipatory andstabilizing means in connection with regulating devices for preventingirregular operation thereof such as hunting or throbbing.

A further object of the invention is to provide improved control systemswhich are capable of decreasing the time lag between the input signaland the initiation of the output response, and of controlling the speedrate of such response.

Another object is a regulating system which provides engine speedregulation to compensate for speed variations due either to load changesor to throttle position changes and does so accurately and elficientlyand without huntmg.

A further object is to provide a device of the type de Figure 3 is asection through an aircraft engine speed regulating system. Figure 4 isa section through a speed regulating system particularly intended for avehicle, and

- When the latter is in its lowermost position a large number Figure 5is a section along the line 5-5 of Figure 4.

Figures 6, 7 and 8 show partial modifications of Figures 1,-

3 and 4, respectively.

The illustrative embodiment shown in Figure 1 includes a hydraulicgovernor 6 having a servo piston 8 for controlling the supply ofactuating substance to a prime mover driving a generator which supplieselectric current to a network 10. Neither the generator nor the primemover is shown in the drawing. A shaft 11 driven from the prime movercarries a gear 12 which engages a companion gear 13 rotatably mounted ona cylindrical extension 14 of the governor body 15. A yoke 16 formed atthe upper end of the gear 13 carries flyballs 18 engaging the collar 20of a pilot valve 21 slidably and rotatably mounted in a bore 22 formedin the governor body 15 coaxial with the cylindrical extension 14. Aspeeder spring 23 applies axial downward load to the pilot valve 21directed against the centrifugal load transmitted thereto by theflyballs 18. An axially adjustable member 24.connected by way of a ballbearing with the spring 23 serves to control the load of the latter andin turn the speed of the prime mover. A governor cover 25, onlypartially shown, may be provided for enclosing the fiyball mechanism andguiding the slidable member 24. In operation of the pilot valve 21 isdriven in rotation by the flyballs 18 owing to the frictiontherebetween.

The pilot valve 21 has lands 26, 28 slidably fitting the bore 22 andfunctioning as plugs to cover and uncover the lateral ports 30 and 31respectively. Between lands 26 and 28 the pilot valve has a portion ofreduced di ameter, and the open space so afforded communicates with alateral passage 32 at all times. The pilot valve is shown in neutralposition, in which both sets of ports 30 and 3 1 are closed. An oilreservoir 33 is provided in the gover-. nor body 15 and communicateswith the flyball compartment, with ports 30 and with the suction side ofa gear pump 34 which may be driven from the governor shaft 11. Thedischarge side of this pump is connected with the ports 31 and with apressure oil accumulator comprising a spring-loaded valve plunger 35slidable in a bore 36 and controlling a by-pass for leading oil back tothe reservoir 33 so as to maintain the oil pressure in the accumulator36 at substantially constant value.

The passage 32 communicates with the servo motor cylinder 38 on theright side of the piston 8. A rod 40 secured to the latter is adaptedfor connection with the control device of the prime mover for regulatingthe supply of energy thereto. Displacement of rod 40 toward the left orthe right will respectively increase or decrease said supply and causean increase or decrease of speed. The cylinder chamber 41 on the leftside of piston 8 is closed by a cover 42 and contains a compressionspring 43 operating on the piston 8 in opposition to the oil pressure inchamber 38. A submerged small orifice 44 whose effective area may beadjusted by means of a needle valve 45 connects the oil reservoir 33with the cylinder chamber 41, and a duct 46 connects the latter with achamber 48 provided at the lower end of the bore 22.

A housing 50 is attached to the governor body 15, with a plate 51interposed therebetween, and includes a flexible diaphragm or bellows 52defining a chamber 53 which,

nut 58. The rate of deflection of bellows 52 may be varied by changingthe axial adjustment of the seat 56.

Q of coils of the springs 54 and 55 are active, and the rate ofdefiection of the bellows has its maximum designed value. If the seat 56is raised both springs are compressed, and an increasing number of thelarger coils thereof come into contact with their seats and becomeineffective, leaving as activecoils those of smaller diameter andtherefore stifier. For the uppermost adjustment of seat 56 the springs54 and 55 may become solidly seated-,-thus reducing-the rate ofdeflection of the'bellows 52 to zero.

A rod 60, attached to the movable Wall of bellows 52 and slidablymounted in a bore provided in the seat 56 isconnected at its lower end.with a solenoid device indicated generally at 59 and including anarmature 61 slidably supported by guides 62, 63 and coacting with asolenoid coil 64 connected with a shunt 65 interposed in one of thesupply lines of the network 10, the voltage across the shunt,proportional to the generator load, being impressed on the solenoid. Anadjustable rheostat 66 and a switch 68 are connected in series with thesolenoid. While this example of solenoid arrangement is intended for adirect current system, the modification thereof for application to analternating current system will be obvious to those skilledin the art.

Assuming that the switch 68 is open, and therefore that the solenoid 59is inoperative, as the prime mover runs at steady speed the fiyballs 18maintain the pilot valve 21 centered in neutral position as shown in thedrawing. The oil-in chambers '41, 48 and 53 has the same pressure as in"the reservoir 33 with which these chambers communicate through theorifice 44. Neglecting the weight of thepilot valve 21, the centrifugalforce and the resilient load applied thereto by the fiyballs 18 and thespring 23 respectively are in equilibrium. If the load on the primemover decreases, the speed increases, and the augmented centrifugalforce lifts the pilot valve thus opening the ports 30, causing dischargeof oil from chamber 38 to the reservoir 33 and displacement of'the servomotor piston 8 toward the r-ight'under the load of the compressionspring 43. This movement of the servo motor decreases thesupply ofactuating substance to the prime mover and causes the speed thereof todecrease.

This speed-decreasing movement of the servo motor would eventually bechecked as the pilot valve resumes its netural position and closes theports 30-, but by this time the prime mover is decelerating and itsspeed would continue to drop below normal, whereupon the diminishedcentrifugal force causes downward movement of the'pilot underspeedcondition of the prime mover does not occur. As the prime mover upon thecorrecting action of the servo motor gradually returns to normal speed,oil from the reservoir 33 flows through orifice 44 into chambers 41, 48and 53, thus progressively returning the bellows 52 to its originalposition of equilibrium and relieving the suction force exerted on thelower end of the pilot valve. The leakage through the orifice 44 isregulated by means of the needle valve 45 in such a manner that thespeed of .theprime mover returns to normal at the same time that the oilpressure in chamber 48 resumes the same value as in the oil reservoir33. Furthermore the rate of deflection of bellows 52 may be adjusted byvarying the axial position of the lower spring valve, the ports 31 areopened and the servo motor piston moves to the left so as to increasethe prime mover supply of actuating substance-and the speed thereof. Thelatter however attains a value higher than the normal speed, and theirregular cyclical speed variation generally re ferred to as hunting islikely to continue indefinitely. To correct this condition ofinstability various compensating or stabilizing arrangements have beenproposed. Accordingito the invention a variable compensating fluidpressure load is applied to one end of the pilot valve, in amanner to belater described. 7

Upon a decrease of load'on the generator, consequent acceleration of theprime mover and. upward displacement of the pilot valve, the servo motorpiston '8 begins to move toward the right and oil is sucked from bellowschamber 53 causing contraction of the bellows 52 from its position ofresilient equilibrium. Only a small amount of 'oil flows into chamber 41from the reservoir 33 through the orifice 44. As a result the oilpressure in chamber 48 temporarily drops below the value of the pressurewhich surrounds the upper end of the pilot valve 21, and a transientdownwardly directed differential pressure load is thus applied to thelatter, and restrains the upward displacement thereof. Although thistransient restraining action exerted on the pilot valve is very small ascompared to the centrifugal'force transmitted thereto'by the fiyballsand by the spring 23, it causes the pilot valve toreturn sufficientlyquickly to its neutral position, so that an seat 56.

When the load on the prime mover is increased its speed decreases andthe action of the governor is the reverse of that just described.Thepilot valve is then pressed down by the spring 23 acting against thedecreased centrifugal force. This opens the ports 31 to admit pressureoil to the cylinder chamber 38 causing displacement of the servo motorpiston 8 to the left and thereby increasing the prime mover supply ofactuating substance. Most of the oil displaced by piston 8 from chamber41 flows to the bellows chamber 53 resiliently expanding the latter,thereby causing increase of oil pressure in chamber 48 so as to exert atransient upward pressure load to the pilot valve to restrain itsdownward movement. As the pilot valve'returns to neutral position uponinitiating the speed correcting action of the servo motor, oil leaksthrough the valve 44, the bellows 52 contracts towards its originalposition of equilibrium, the oil pressure in chamber 43 resumes theatmospheric value, and the pressure load exerted on the pilot valvereturns to zero. This transient restraining act-ion exerted upon thepilot valve 21 and tending to return the same to neutral position isproportional to the square of the speed of motion of the servo piston 8and therefore is effective to maintain the rate of motion of saidpiston, hence the rate of variation of the conditioncontrolled thereby,within desired limits even for high rate of change-of the input signalapplied to the pilot valve. The foregoing restraining action will bemore fully set forth in connection with Figure 2.

The abovemanne'r of operation is obtained when the switch 68 is open,with the solenoid coil 64 not energized and the armature 6 1inoperative. However, when the switch 68 is closed the solenoid isenergized and a down- Wardly directed electromagnetic load proportionalto the generator'load is applied to the armature 61 and is transmittedby means of the rod 60 to the bellows 52. If the load on the generatorsupplying the network 10 increases suddenly, the current energizing thesolenoid 64' increases accordingly causing a sudden increase of thedownward pull that the armature 61 exerts on the bellowsSZ. The latterwill tend to expand, causing suction in chamber 48 and-determining adownward movement of the pilot valve so as to uncover the ports 31 andinitiate a movement of the servomotor piston 8 in a direction toincrease the supply of actuating substance to the prime mover evenbefore the fiyballs 18 have detected a drop of speed. The reverse actionoccurs upon a sudden decrease in electric load in the network 10 whichdetermines a decrease ofthe-downward pull transmitted by the armature 61to the bellows'52. The latter tends to move upward, in creasing the oilpressure in chamber 48 and determining an upward displacement of thepilot valve 21 so as to open ports 30 and initiate an excursion of theservo motor piston 8 in a speed-decreasing direction in anticipation ofthe prime mover acceleration which would otherwisefollowthe reduction ofload.

It will be noted-that the solenoid device 59 actuates the pilot valve inthe same manner asand ahead of the time at which the latter wouldotherwise be actuated by the fiyballs, so 35 120 compensate for thedelay in the response of the. g Q rnor andreduce the magnitude of thespeed surges occurring under sudden variations of load. Owing to theleakage valve 44 the action of the solenoid device 59 on the pilot valve21 is of temporary nature. The amount of compensation effected by thesolenoid may be adjusted by means of the rheostat 66, and by means ofthe seat 56 which serves to regulate the rate of deflection of thebellows 52.

It will be appreciated that the oil displacement in chamber 41 due tomovement of the servo'motor piston 8 is many times larger than the oildisplacement in chamber 48 caused by sliding motion of the pilot valve21. For the purpose of rendering a numerical example more simple it maybe assumed that the seat 56 is adjusted in its uppermost position so asto block the diaphragm 52. In which case as the pilot valve 21 or thepiston 8 are moving at a given velocity, the corresponding velocity ofthe oil forced through the orifice 44 is proportional to the square ofthe effective diameter of said valve or piston, and the change ofpressure in chamber 48 is proportional to the fourth power of saiddiameter. Assuming for instance that the face of the piston 8 definingchamber 41 have an effective diameter four times as large as that of thepilot valve, when the piston 8 is moving at a certain velocity itdetermines a transient relative pressure in chamber 48 which is 25 6times as large as that occurring when the pilot valve 21 is moving atthe same velocity. It will therefore be readily understood that wherethe diameter and stroke of piston 8 are so designed in relation to thepilot valve 21, the orifice 44, suitably adjusted by means of the needlevalve 45 for correct operation of the governor, will not oppose anyappreciable resistance to the free motion of the pilot valve. The dangerthat chamber 48 may operate as an objectionabledashpot for the pilotvalve and prevent rapid displacement of the latter in response to rapidspeed changes, thus resulting in serious overspeed or underspeed uponsudden load variations may therefore be entirely avoided.

Where no anticipatory actuation of the pilot valve by means of theelectromagnetic device 59 is desired, the solenoid 5 and the rod 60 maybe omitted. Furthermore in substitution for the resiliently loadedbellows 52 other equivalent cushioning means may be provided, such as aresiliently loaded slidable piston, or an air accumulator communicatingwith chamber 48.

Figure 2 shows a partial modification of Figure l indicating an airchamber or accumulator 70 provided in the lower portion of the pilotvalve in substitution for the bellows chamber 53, the governor beingotherwise similar to that of Figure 1. It will be appreciated that thisform of governor is extremely simple, compact and contains a very smallnumber of moving parts as compared to other isochronous governors. Itwill be noted that in the arrangement shown in Figure 2 the air chamber70, formed within the lower end of the pilot valve, is very small andthe cushioning effect thereof is quite limited. If we assume that thisform of governor is used to control a variable-speed powerplant, thatthe latter is operating at low governed speed, and that the operatorsuddenly moves the control lever to full-speed setting, then the load.of the governor spring 23 will be instantly increased to its maximumdesigned load corresponding to maximum speed of the powerplant, and as aresult the pilot valve 28 will be shifted all the way downward, fullyopening the port admitting hydraulic fluid from the high pressure system31, 36 to the cylinder chamber 38. This motion of the pilot valve willnot cause any objectionable pressure rise in the hydraulic fluid at thelower end thereof, as the small volume of fluid displaced by the pilotvalve is in part discharged at low velocity through the orifice 44,while the remainder causes a slight compression of the air in thecushion chamber 76. However, the ensuing motion of the piston 8 towardthe left displaces fluid at amuch higher rate, causing a substantialincrease in pressure. The air in the cushion chamber 70 soon contractsto a very small volume, whereupon substantially all of the fluiddisplaced by the power piston 8 must be discharged through the smallorifice 44. The resulting increase in fluid pressure exerts on the lowerend of the pilot valve 21 a restraining action tending to return thesame to its neutral position, which action is proportional to the squareof the speed of motion of the servo piston 8, and is therefore effectiveto limit the rate of motion thereof. It will be appreciated that bysuitably adjusting the effective area of the orifice 44 the maximum rateof motion of the servomotor, and in turn the maximum rate of change inthe condition being controlled, may be limited to any desired orpredetermined value, said rate varying in relation to the magnitude andsuddenness of the input signal or load exerted upon the pilot valve.

In the above disclosed arrangement the governor is adapted to increaseor decrease the supply of energy to a prime mover in response todeceleration or acceleration of the latter due to increase or decreaseof the load applied thereto respectively. A dilferent arrangement isshown in Figure 3, wherein a governor 6 operates to in crease ordecrease the load applied to a powerplant 75 in response to decelerationor acceleration of the latter respectively, independently of the supplyof energy thereto. A hydraulic governor indicated generally at 6 isdriven by means of a shaft 11 and gears 72, 73 from an aircraft engine75 indicated diagrammatically in reduced scale and connected with avariable pitch propeller having blades 76 automatically controlled bythe governor 6 so that their pitch is automatically modified inaccordance with variations in the speed of the engine. To this end eachblade 76 is rotatable about a spider arm attached to the propeller shaft78. The latter has an internal chamber and is furnished with acylindrical cap 81 which is 1ongitudinally movable on the shaft 78 underhydraulic pressure supplied to the chamber 80 from the governor 6'. Thecap 81 has two studs 82 which engage slots in lugs 83 carried by theblades 76. When the propeller is in operation centrifugal andaerodynamic forces tend to turn the blades 76 into coarse or maximumpitch against said hydraulic pressure.

The governor 6 may be similar to that disclosed in connection withFigure 1 except that it does not include the bellows chamber 53 nor thesolenoid device 59. Furthermore the hydraulic servo motor member or cap81 is substituted for the servo motor piston 8 of Figure 1.

Under steady flying conditions the pilot valve 21 is in neutralposition. If the engine speed increases, as may be due to a dive or toincreased manifold pressure, the pilot valve is lifted by the flyballsso as to open the ports 30, pressure oil flows from the propellerchamber (which is in direct communication with chamber 80) through ducts182, 183 to the reservoir 33, the cap 81 moves to the right causing thepropeller pitch to be increased, and the augmented propeller torqueslows the engine down to normal speed. Conversely, when the engine speeddecreases, as may be due to a climb or'to decreased engine manifoldpressure, the pilot valve drops and opens the ports 31 to admit pressureoil to the servo motor chamber 180, whereupon the cap 81 moves outwardlyand decreases the propeller pitch and the propeller torque until theengine resumes normal speed. It has been found that owing to theconsiderable inertia of the propeller and to the character of theresistance of the air to the rotation thereof, hunting can be avoidedwithout resorting to compensating devices in the governor. It istherefore unnecessary to provide means for applying a variable operativefluid pressure load at one end of the pilot valve, and hydraulicgovernors adapted for the control of constant speed propellers and notincluding any compensating means are well known in the art. According tothe invention, however, a variable pressure oil chamber 48 is providedat the lower end of the pilot valve 21 and communicates by means of aleak valve 44' adjustable by way of needle valve 45' with the reser- 7voir 33, and by means of conduits 90 and 91 with the cylinders 86 and88. A piston 92 slidable in cylinder 86 is connected by a rod 93 with aflexible diaphragm 94 mounted between two cup members 95 and 96 andprovides two separate chambers 98 and 100 therein. Springs 101 and 102are mounted on either side of the diaphragm.

A pressure tube anemometer or Pitot tube 104- includes an open endedinner tube 105 facing the air stream for measuring the total pressurehead, and a concentric outer tube 106 having lateral orifices 107 soarranged as to measure the static pressure. The former and latter tubesare connected with chambers 100 and 98 respectively. If the aircraft airspeed suddenly increases as it occurs when a dive is initiated the totalpressure head in chamber 100 increases, causing displacement of piston92 toward the left so as to temporarily increase the oil pressure inchamber 48. The pilot valve is lifted and the propeller cap 81 slidestoward the right so as to increase the propeller pitch in advance of thetime at which the pilot valve would otherwise have been lifted upon anincrease of the centrifugal force transmitted thereto by the flyballs.This advance actuation of the pilot valve by means of the anemometerconsiderably reduces the engine speed surge that would otherwise occur.Conversely, when the aircraft air speed suddenly decreases, as when aclimb is initiated, the total pressure head in chamber 100 decreases,moving the piston 92 toward the right, creating suction in chamber 48'and causing the pilot valve to drop so as to initiate an outwardmovement of the cap 81 to decrease the propeller pitch ahead of the dropof engine speed which would occur with a conventional governor. Thelower cylinder 88 is provided with a piston 109 connected by a rod witha flexible resiliently loaded diaphragm 110 separating chambers 111 and112. The former is vented to the atmosphere, and the latter is connectedby a pipe 114 with the engine manifold 113. A sudden increase of theengine manifold pressure determines a displacement of the diaphragm 110and piston 109 toward the left and transiently increases the oilpressure in chamber 48 so as to lift the pilot valve 21 and increase thepropeller pitch in anticipation of the increase of engine torque. Theactuation of the pilot valve 21 by means of the diaphragm 110 and 94 hasa temporary character owing to the action of the leak valve 44'.

A still further form of governor, indicated generally at 120, is shownin Figures 4 and 5, wherein a differential oil pressure varying with thespeed of the prime mover is employed instead of the centrifugal forcefor actuating the pilot valve in response to speed variations. Thegovernor 120 includes a housing 121 comprising a gear pump having anidler gear 122 meshing with a driving gear 123 which is keyed to a shaft124 supported in bearings formed in the pump housing 121 and in thegovernor body 125. The shaft 124 carries a gear 126 adapted to be drivenfrom the prime mover. A bore 128 coaxial with shaft 124 is formed in thegovernor body 125, and lateral ports 130, 131 and 132 are connected withsaid bore. A pilot valve 133 slidably and rotatably mounted in said boreis formed with an intermediate portion of reduced diameter, thusproviding an annular open space communicating with ports 131 at alltimes. The terminal portions of the pilot valve control the ports 130and 132. When the pilot valve is in neutral position as shown in thedrawing the ports 130 and 132 are closed. The ports 132 are connectedwith a reservoir 134 containing oil at atmospheric pressure, while theports 130 are connected with an oil accumulator 135 wherein the pressureis kept substantially constant by means of a slidable resiliently loadedpiston 136 controlling suitable ports.

The passage 131 leads pressure oil to and from the cylinder chamber 138for actuating the'difierential servo motor piston 140, the arrangementbeing such that a displacement of thelatter toward the right tends toincrease the speed of the prime mover. The cylinder chamber 141 at theopposite side of the piston may contain a compression spring 142 forresiliently loading the latter, and communicates with an air chamber 143and, by way of duct 144, with a chamber 145 at the left side of thepilot valve 133. An orifice 146 adjustable by a needle valve 148 isprovided between said chamber 145 and a chamber 150 which communicateswith the discharge sideof the oil pump 123. A duct 151 connects thechamber 152 at the right end of the pilot valve with theoil accumulator135. The pressure chamber 150 communicates with the oil accumulator byway of an orifice 153 adjustable by means of a resiliently loaded needlevalve 154 actuated through a cam 156 by a speed control lever 155. Acoil spring 158 has its terminal coils securely attached to the shaft124 and to the pilot valve 133 so as to drive the latter along inrotation with the former.

The pump 123 discharges a quantity of oil proportional to the speed ofthe prime mover through the orifice 153 thus determining on oppositesides of the latter a dilference of pressure proportional to the squareof said speed; this oil flows to the accumulator 135 and thence throughports 160 returns to the reservoir 134 connected with the suction portof the pump. As the upstream and downstream sides of the orifice 153 arein communication with chambers 145 and 152 respectively, an axial oilpressure differential load proportional to the square of the speed anddirected toward the right is applied to the pilot valve 133. Duringsteady operation this load is balanced by the tension of the spring 158,and the pilot valve 133 is in neutral position as shown in the drawing.If now the speed of the prime mover increases, the oil delivery and inturn the diiference of pressure between chambers 145 and 152 increases,causing displacement of the pilot valve toward the right so thatpressure oil is discharged from the cylinder 138 into the reservoir 134.The servo motor piston moves toward the left, tending to decrease thespeed of the prime mover. The increase of volume of the cylinder chamber141 causes an affiux of oil thereto from the air chamber 143 and throughthe orifice 146 thus causing a temporary drop of pressure in chamber145. This restrains the excursion of the pilot valve toward the rightand prevents overtravel of the latter, as it has already been disclosedin connection with Figure 1, so as to eliminate hunting. Conversely,when the prime mover decelerates the difference of oil pressure betweenchambers 1'45 and 152 drops below the tension of spring 158, causesdisplacement of the pilot valve toward the left and consequent movementof the servo motor piston 140 toward the right tending to increase theprime mover speed. Part of the oil so displaced from chamber 141 flowsinto chamber 143 against increasing pressure of the air therein, andpart is forced through the restricted orifice 146. The temporary oilpressure increase in chamber restrains the excursion of the pilot valvetoward the 'left and prevents overcorrection on the part of the servomotor. As the speed gradually returns to normal, owing to the leak valve146 the pressure in chambers 145, 143 and 141 progressively resumes thesame value as in chamber 150.

The speed at which the governor maintains the prime mover is dependentupon the effective area of the orifice 153. Inward or outward movementof the needle valve 15 4 obtained by adjusting the speed control levercauses decrease or increase of said area and determines decrease orincrease of said speed, respectively. Unlike the governors provided withcentrifugal fiyballs the governor 120 has the same regulating energy atall speeds.

When the governor is employed for the speed regulation of a prime moverused for the propulsion of a vehicle such for example as a locomotive orotherrailroad or highway vehicle, a device responsive to angularacceleration as diagrammatically shown in smaller scale at 162 may beemployed for the anticipatory actuation ,of

the pilot valve thereof. A cylinder 163' secured to the prime mover orother fixed part of the vehicle has slidably mounted therein a piston164 connected by a rod 165 with a lever 166 pivoted on the axis 168 andcarrying at its ends weights 170 whose distance from the axis 168 may beadjusted by means of their threaded connection with lever 166. Thecenter of gravity of the oscillating system including lever, piston andconnecting rod is located at the center of the pivot 168. This system isthus in indifferent equilibrium and the angular adjustment thereofrelative to the cylinder 163 does not vary upon any translationalacceleration of the vehicle. The cylinder chamber 171 above piston 164is connected by way of a conduit 172 provided with a dampening orificeadjustable by means of a needle valve 173 with the servo motor cylinder141. Springs 174 may be provided tending to hold the oscillating leverin preselected position. It is assumed that the vehicle equipped withthe regulator 162 proceeds in the direction of arrow V. As long at isadvances on constant grade the piston 164 remains stationary but as soonas a steeper upward grade is encountered and both the vehicle and thecylinder 163 undergo a slight counter-clockwise rotation about an axisparallel to the pivot 168 the inertia of the oscillating system 166causes a downward movement of piston 164 relative to the cylinder 163and oil is sucked from chamher 141. The oil pressure in chamber 145drops, the pilot valve moves toward the left so as to initiate adisplacement of the servo motor piston 140 toward the right tending toincrease the speed of the prime mover in advance of the time at whichdeceleration otherwise resulting would be detected by the governor. Thetemporary deceleration of the vehicle is thus substantially reduced.Conversely, when a downward directed grade variation is encountered, -aslight clockwise rotation of the cylinder 163 occurs, the piston 164moves inward relatively to the cylinder forcing oil into chamber 141,and displacing the pilot valve 133 toward the right so as to initiate amovement of the servo motor in a direction to decrease the speed of theprime mover.

It will be readily understood that the angular acceleration responsivedevice 162 may also be used in connection with centrifugally actuatedgovernors such as 6 and 6' as shown in Figure 6. It may be furtheremployed in aircraft installations in substitution for the anemometer104 to actuate the governor pilot valve so as to initiate a propellerpitch increasing or decreasing movement of the servo motor as soon asthe aircraft initiates a dive or a climb, respectively, as shown inFigure 7. In these aircraft applications gyroscopic means may beadvantageously substituted for the comparatively heavy and bulkyoscillating lever 166, as will appear obvious to those skilled in theart. Such a substitution is shown in Figure 8, in which the piston 164is positioned through a rod 165' from a gyroscope 180 which may be ofcon ventional construction and which is well known in the art as anelement.

While the hydraulic medium used in the various governors disclosed hasbeen referred to as lubricating oil, any other appropriate fluid may beused in substitution therefor. In the above disclosed speed regulatingsystems a decrease of pressure of the fluid actuating the servo motorthereof causes a reduction of speed of the prime mover. For example, inFigure l a pressure drop in the cylinder chamber 38 causes a movement ofthe piston -40 to the right which, as indicated by the arrow, determinesa reduction of prime mover speed. This may be considered a safetyfeature, for an accidental interruption in the supply of the actuatingpressure fluid to the servo motor, as may be due to failure of the fluidpump or rupture of a fluid conduit causes the prime mover to stop. WhileI have shown and described only certain preferred embodiments of myinvention by way of illustration, many modifications will occur to thoseskilled in the art and I therefore wish to have it understood that Iintend in the appended claims to cover all such modifications as fallwithin the true spirit and scope .of my invention. And where claims aredirected to less than all the elements of the complete system disclosed,they are intended to cover possible uses of the recited elements ininstallations which may not include the nonrecited elements.

I claim:

1. A hydraulic governor for a variable pitch propeller driven by anaircraft propulsion powerplant having an air induction system,comprising a hydraulic pressure operated regulator member forcontrolling the blade angle of the propeller, a pilot valve movable inopposite directions to move said regulator member in oppositedirections, powerplant speed responsive means for moving the pilotvalve, a fluid pressure chamber and a piston movable directly with saidpilot valve for compressing and expanding said chamber upon movement ofthe pilot valve in opposite directions, a first accumulator chamberincluding first movable wall means and resilient means normallyretaining said first wall means in a neutral position, a secondaccumulator chamber including second movable wall means and resilientmeans normal- 1y retaining said second wall means in a neutral position,said first and second accumulator chambers being in free fluidcommunication with said fluid pressure chamber, a pressure responsivedevice connected with the air induction system of the powerplant forvarying the neutral position of the first 'wall mean-s in response tochanges of pressure in said induction system, and aircraft velocitymeasuring apparatus -for modifying the neutral position of the secondwall means in response to variations in aircraft velocity.

2. A hydraulic governor for aircraft propulsion powerplant having an airinduction system and driving a variable-pitch propeller, comprisinga'hydraulic pressure operated regulator member for varying the propellerpitch, a pilot valve movable in opposite direct-ions to move saidregulator member in opposite directions, powerplant speed responsivemeans for moving'saidpilot valve, a fluid pressure chamber and apistonmovable directly with said pilot valve for compressing andexpanding said chamber upon movement of the pilot valve in oppositedirections, a first compensating chamber including first movable wallmeans and resilient means normally retaining said first wall means in aneutral position, a second compensating chamber including second movablewall means and resilient means normally retaining said second wall meansin 'a neutral position, said first and second compensating chambersbeing in free fluid communication with said fluid pressure chamber,leakage means connected with said chambers for dissipating in time thepressure variations therein, a pressure responsive device connected withthe air induction systern of the powerplant for varying the neutralposition of the first wall means in response to changes of pressure insaid induction system, and aircraft [velocity measuring apparatus formodifying the neutral position of the second wall means in response tovariationsin aircraft velocity.

3. A hydraulic governor for aircraft propulsion powerplant having an airinduction system and driving a variable-pitch propeller, comprising ahydraulic pressure operated regulator member for varying the propellerpitch, a pilot valve movable in opposite directions to move saidregulator member in opposite directions, powerplant speed responsivemeans for moving the pilot valve, a fluid pressure chamber and a pistonmovable directly with said pilot valve for compressing and expandingsaid chamber upon movement of the pilot valve inopposite directions, afirst compensating chamber including first movable wall means andresilient means normally retaining said first wall means in a neutralposition, a second compensating chamber including second movable wallmeans and resilient means normally retaining said second wall means in aneutral position, said first and second compensating chambers being infree fluid communication with .said fluid pressure chamber, leakagemeans connected with said chambers, a pressure responsive deviceconnected with the air induction system of the powerplant for varyingthe neutral position of the first wall means, and aircraft velocitymeasuring apparatus for modifying the neutral position of the secondwall means.

4. In governing apparatus for a variable pitch propeller driven by anaircraft propulsion powerplant having an air intake system, thecombination with input means responsive to changes in powerplant speedand output means for controlling the blade angle of the propeller, of amechanism having a servo motor for variably positioning said outputmeans, a movable control element for controlling said servo motor, meansfor actuating said control element from said input means, means for providing a space for fluid under variable pressure, a surface area movablewith said control element and subject to the fluid pressure in saidspace for applying to said control element in the direction of motionthereof a force proportional to said fluid pressure, first and secondwall means each movable to vary the fluid pressure therein and actuatesaid control element, a sensor device responsive to change of aircraftspeed for moving one of said wall means, and a second device responsiveto variations of pressure in said air intake system for moving the otherwall means.

5. In a governing system for a variable pitch propeller driven by anaircraftpropulsion powerplant, the com bination with input meansresponsive to changes in powerplant speed and output means forcontrolling the blade angle of said propeller, of a mechanism having aservo motor for variably positioning said output means, a movablecontrol element for controlling said servo motor, means for actuatingsaid control element from said input means, a fluid pressure chamber,leakage means connected to said chamber for dissipating in timethepressure change therein, a surface area movable with said controlelement and subject to the fluid pressure in said chamber for applyingto said control element in the direction of motion thereof an actuatingforce proportional to the pressure in said chamber, said chamberincluding wall means movable to alter the fluid pressure therein andactuate said control element, and a Pitot tube sensing variations ofaircraft air speed for moving said wall means to cause transientvariations in the blade angle of the propeller upon changes ofaircraftair speed.

6. In a governing system for the variable pitch propeller of an aircraftpropulsion powerplant, the combination with regulating means movable toadjust the blade angle of the propeller,'of a servomotor for actuatingsaid regulating means, a. movable control element. for controlling theservomotor, powerplant speed responsive means for actuating said controlelement in the direction tending to maintain substantially constantpowerplant speed, a fluid'presSure chamber, leakage means connected withsaid chamber for dissipating the pressure change therein, first wallmeans movable with said control element and subject to the pressure offluid in said chamber for applying to said control element in thedirection of motion thereof an actuating force proportional to thepressure in said chamber, second wall means movable to set up pressurevariations therein, and means responsive to variations of aircraftvelocity for moving the second wall means in the sense tendingtransiently to decrease or increase the powerplant speed upon increaseor decrease of aircraft velocity, respectively.

7. In a governing system for the variable pitch propeller of an aircraftpowerplant having an air intake system, the combination with regulatingmeans for adjusting thebla'de angle of the propeller, of a servomotorfor operating said regulating means, a control element for controllingthe servomotor, powerplant speed responsive means for actuating saidcontrol element in a direc: tion tending to maintain substantiallyconstant powerplant 'speed, a fluid pressure chamber, first wall meansmovable with said control element and subject to the pressure of fluidin said chamber for applying tosaid control elementin the direction ofmotion thereof an actuatingforce proportional to the pressure in saidchamber, second and third wall means each movable to cause pressurevariations therein, means responsive to a function of 'the'aircraftvelocity for moving the second wall means, and means responsive to afunction of the pressure in said air intake system for moving the thirdwall means.

8. In a governing apparatus for the variable pitch propeller of anaircraft engine, the combination with regulating means for varying theblade angle of the propeller, of motor means for actuating saidregulating means, a control member for controlling said motor means,engine speed responsive means for moving said control member, a fluidpressure chamber, means for moving said control member in response topressure variations in said chamber, movable wall means for causingpressure variations therein, and means responsive to motion of theaircraft indicating the initiation of climb or dive for actuating saidwall means.

9. In a governor for a variable pitch propeller driven by an aircraftengine, the combination with regulating means operable to increase ordecrease the blade angle of the propeller, of motor means for actuatingsaid regulating means, a control member for controlling said motormeans, engine speed responsive means for actuating said control member,a fluid pressure chamber, means for moving said control member inresponse to pressure variations in said chamber, movable wall means forcausing pressure variations therein, and gyroscopic means sensinginitiation of climb or dive of the aircraft for actuating said wallmeans.

10. In governing apparatus for aircraft propulsion powerplant having avariable pitch propeller and an air intake system, the combination withinput means responsive to changes in powerplant speed and output meansfor controlling the blade angle of said propeller, of a mechanism havinga servo motor for variably positioning said output means, a movablecontrol element for con trolling said servo motor, means for actuatingsaid control element from said input means, means for providing a spacefor fluid under variable pressure, a surface area movable with saidcontrol element and subject to the fluid pressure in said space forapplying to said control element in the direction of motion thereof aforce proportional to'said fluid pressure, a source of fluid atsubstantially constant pressure, leak orifice means for connecting saidspace with said source, first and second wall means each movable toalter the volume of said space for transiently varying the fluidpressure therein and actuating said'control element, a sensor device"responsive to change of aircraft speed for moving one of said wallmeans, and a second device responsive to variations of pressure in saidair intake system for moving the other wall means.

11. In a governing system for aircraft propulsion powerplant having avariable pitch propeller, the combination with input means responsive tochanges in powerplant speed and output means for controlling the bladeangle ofsaid propeller, of a mechanism having a servomotor for variablypositioning said output means, a movable control element for controllingsaid servo motor, means for actuating said control element from saidinput means, a fluid'pressure chamber, a surface area movable with saidcontrol element and subject to the fluid pressure in said chamber forapplying to said controlelement inthe direction of motion thereof anactuating force proportional to the pressure in said chamber, a sourceof fluid at substantially constant pressure, leak orifice means forconnecting said source with said chamber to dissipate gradually thepressure variations in said chamber, said chamber including wall meansmovable to alter the volume of said chamber for transiently varying thefluid pressure therein and actuating said control element, and a Pitottube sensing variations of air speed for moving said wall means.

12. In a governing system for the variable pitch propeller of anaircraft propulsion powerplant, the combination with regulating meansmovable to adjust the blade angle of the propeller, of a servomotor foractuating said regulating means, a movable control element forcontrolling the servomotor, powerplant speed responsive means foractuating said control element to maintain substantially constantpowerplant speed, a fluid pressure chamber, first wall means movablewith said control element and subject to the pressure of fluid in saidchamber for applying to said control element in the direction of motionthereof an actuating force proportional to the pressure in said chamber,leak orifice means for gradually dissipating the variations of pressurein said chamber, second wall means movable to alter the volume of saidchamber for setting up transient pressure variations therein, and meansresponsive to variations of aircraft velocity for moving the second wallmeans in the sense tending to decrease or increase the powerplant speedupon increase or decrease of aircraft velocity, respectively.

13. In a governing system for the variable pitch propeller of anaircraft powerplant having an air intake system, the combination withregulating means for adjusting the blade angle of the propeller, of aservomotor for operating said regulating means, a control element forcontrolling the servomotor, powerplant speed responsive means foractuating said control element to maintain substantially constantpowerplant speed, a fluid pressure chamber, first wall means movablewith said control element and subject to the pressure of fluid in saidchamber for applying to said control element in the direction of motionthereof an actuating force proportional to the pressure in said chamber,leak orifice means for gradually dissipating the variations of pressurein said chamber, second and third wall means each movable to alter thevolume of said chamber for causing transient pressure variationstherein, means responsive to a function of the aircraft velocity formoving the second wall means, and

means responsive to a function of the pressure in said air intake systemfor moving the third wall means.

14. In a governing apparatus for the variable pitch propeller of anaircraft powerplant, the combination with regulating means for varyingthe blade angle of the propeller, of motor means for actuating saidregulating means, a control member for controlling said motor means,means for moving said control member upon changes of powerplant speed, afluid pressure chamber, means for moving said control member in responseto pressure variations in said chamber, a leak valve for dissipating intime the pressure changes in said chamber, movable wall means forvarying the volume of said chamber and causing transient pressurevariations therein, and gyroscopic means sensing changes in aircraftattitude indicating the initiation of climb or dive for actuating saidwall means.

15. In a governor for the variable pitch propeller of an aircraftengine, the combination with regulating means operable to increase ordecrease the blade angle of the propeller, of motor means for actuatingsaid regulating means, a control member for controlling said motormeans, engine speed responsive means for actuating said control memberto maintain the engine speed substantially at a desired value, a fluidpressure chamber, means for moving said control member in response topressure variations in said chamber, a leak valve for dissipating intime the pressure changes in said chamber, movable wall means forvarying the volume of said chamber and causing transient pressurevariations therein, and gyroscopic means for actuating said wall meansupon initiation of aircraft climb or dive.

References Cited in the file of this patent UNITED STATES PATENTS2,233,307 Dodson Feb. 25, 1941 2,245,562 Becker June 17, 1941 2,252,693Becker Aug. 19', 1941 2,396,321 Goddard Mar. 12, 1946 2,407,317Mennesson Sept. 10, 1946 2,410,774 Chandler Nov. 5, 1946 2,516,828Reggio July 25, 1950 2,769,432 Massey Nov. 6, 1956 2,812,746 Reggio Nov.12, 1957

